When a compressor connected drivingly with a driving apparatus fails to operate by chance due to seizure of sliding portions or like troubles, it is liable to consequently damage the driving apparatus because of the overload applied thereto.
In a recent trend wherein the compressor of a vehicle air conditioning system is so designed as to be operated in a common driving system or apparatus, and being driven by power from an engine for driving the car, together with a water pump, an alternator, etc., through a single belt, a possible breakage of the belt due to failure of the compressor may give rise to overheating of the engine, which can lead to serious engine problems.